The present invention relates generally to cost-effective methods and apparatuses for interfacing a thermal storage system with an existing or new air conditioning system. More specifically, the present invention relates to an efficient method and apparatus for using a recycled water loop as a coolant fluid to augment an existing cooling system.
The present invention is directed to a simple and cost-effective method for interfacing a thermal storage system with an existing or new air conditioning unit to produce cooling system performance benefits.
Thermal storage units and systems are known. However, integrating such units and systems into a fully functional air conditioning system has provided the field with significant challenges. Three basic methods are traditionally used to accomplish this integration. First, air coupled systems are used whereby cool air charges this cool storage media and warm air is passed over a cool storage media to be cooled when the thermal storage system is discharged. See, for example, U.S. Pat. No. 4,922,998. Second, a secondary fluid is used to both charge a cool storage reservoir and to discharge the cool storage reservoir. Here an additional heat exchanger or the heater core (with the hot engine coolant valved off) is used as the air cooling means. See, for example, U.S. Pat. No. 5,277,038. In a special embodiment of this, an evaporator having (in addition to the fins in intimate contact with passages for evaporating refrigerant) a second set of passages also is in intimate contact with the aforementioned fins. A heat exchange fluid, such as an ethylene glycol/water mixture is caused to flow between a cool storage system and through this second set of evaporator passages. The heat exchange fluid and the refrigerant passages is interleaved to maximize heat transfer from the heat exchange fluid to the evaporating refrigerant during the charge. Note that essentially all heat transfer from the store is carried by fin conductivity between the two sets of passages. For the discharge cycle, cold fluid is passed through this special evaporator to remove heat from the air flowing over the fins. Third, a separate refrigeration loop is used that is suitably valved to evaporate refrigerant in passages within the storage reservoir and cool (charge) the contents of the store. A heat exchange fluid that can be caused to flow through the store is used on discharge to transfer heat (using a heat exchanger) from the air in the conditioned volume to the store.
In air coupled systems large volumes of air must be moved over the thermal storage system in a manner that does not restrict airflow. This usually means that the relatively large cool store has to be in close proximity to the system evaporator, which can present difficulties with respect to available space relative to the size of the components involved. A secondary fluid system certainly provides the flexibility of location, but adds another loop to the system as well as at least one more heat exchanger. The separate refrigerant loop adds a heat exchanger to the store and necessitates redistribution of refrigerant into added high pressure a/c lines. These additional components complicate installation and operation, and allow for potentially undesirable oil migration.
According to one preferred embodiment, the present invention is directed to a method for cooling an air stream. In a discharge cycle, a thermal storage reservoir is provided having an inlet and an outlet, said reservoir preferably comprising a phase change material. A thermally conductive heat exchanger having an inlet and an outlet is provided, with the inlet and outlet directing the flow of a heat exchange fluid through the heat exchanger. A primary water loop is provided having an amount of water directed through a conduit to the thermal storage reservoir inlet and away from the reservoir through the reservoir outlet, such that said water temperature decreases as the water is directed from the reservoir outlet. A fluid disperser, having a disperser inlet and a disperser outlet, is provided in communication with the conduit such that water in the water loop is directed from the reservoir to the dispenser inlet. Water is then dispersed from the conduit through the disperser outlet and onto the surface of the heat exchanger. Excess water from the heat exchanger surface as well as condensation from the heat exchanger (depending on ambient conditions) is collected and reclaimed in a collector and directed to the reservoir to continuously feed the water loop. Finally, an airflow is provided having a first temperature in the direction of the heat exchanger. The airflow moves past the heat exchanger such that the air, after passing the heat exchanger, has a second temperature lower that the first temperature.
In another embodiment, the present invention is directed to an apparatus for cooling air comprising a thermal storage reservoir having an inlet and an outlet, the reservoir preferably comprising a phase change material. In a discharge cycle, a thermally conductive heat exchanger is provided having an outer surface and an inlet and an outlet, said inlet and outlet directing the flow of a heat exchange fluid into and out from the heat exchanger. A primary water loop having an amount of water directed through a conduit inlet to the thermal storage reservoir inlet and away from the reservoir outlet is in communication with the reservoir, such that said water temperature decreases as the water is directed away from the reservoir outlet and through the conduit in the direction of the heat exchanger. A fluid disperser having a disperser inlet and a disperser outlet is provided in communication with the conduit such that water in the water loop is directed from the reservoir outlet through the conduit to the disperser inlet. A device such as a blower is provided for creating airflow having a first temperature, the airflow directed in the direction of the disperser and past the heat exchanger such that the airflow has a second temperature after passing the heat exchanger that is less than the first temperature. A collector for collecting and reclaiming water from the outer surface of the heat exchanger is in communication with the conduit inlet to provide a continuous feed of water into the water loop.
In yet another embodiment, the present invention is directed to a method for cooling an air stream. A primary refrigerant loop is provided comprising a heat exchanger, and preferably, a compressor and condenser. A secondary water loop, preferably an open water loop, is provided having an amount of water directed through the heat exchanger, such that the water temperature decreases as the water is directed away from the heat exchanger. A fluid disperser is provided having a disperser inlet and a disperser outlet. The disperser is provided in communication with the second conduit such that water in the secondary water loop is directed away from the heat exchanger to the disperser inlet. Water is dispersed from the conduit through the disperser outlet and onto a thermally conductive water contacting surface located proximate to, and preferably downstream from the disperser outlet. An airflow having a first temperature is then directed in the direction of the water contacting surface and past the water contacting surface, such that the airflow, after passing the water contacting surface, has a second temperature lower that the first temperature. An amount of water is collected and reclaimed for the water loop from the surface of the water-contacting surface and directed through the water loop to the second reservoir inlet on the reservoir. Optionally, a thermal storage reservoir can be placed in communication with either or both of the primary refrigerant loop and the secondary water loop.
In still another embodiment, the present invention is directed to an apparatus for cooling air comprising a refrigerant loop in communication with a water loop, preferably an open water loop. A primary refrigerant loop is provided comprising a first conduit in communication with a heat exchanger, compressor and condenser, with an amount of refrigerant circulating through the primary refrigerant loop. A secondary water loop is provided having an amount of water directed through a second conduit to the heat exchanger and to a fluid disperser, such that said water temperature decreases as the water is directed away from the heat exchanger. A thermally conductive water contacting surface is located proximate to the disperser for receiving water dispersed thereon from the disperser outlet and onto the surface of the water contacting surface. A blower is provided for creating an airflow in the direction of the water contacting surface and past the water contacting surface. The airflow has a first temperature from the blower and is directed such that the airflow, after passing the water contacting surface, has a second temperature lower that the first temperature. A collector is positioned proximate to the water contacting surface for collecting and reclaiming water from the surface of the water contacting surface. The collector is in communication with the secondary water loop inlet. Optionally, a thermal storage reservoir can be placed in communication with either or both of the primary refrigerant loop and the secondary water loop.